KR20100066875A - Handover apparatus and method for preventing time delay in the heterogeneous networks - Google Patents

Abstract

PURPOSE: A handover apparatus between heterogeneous networks and a method thereof for supplying a seamless service by reducing data loss are provided to reduce handover time delays by selecting an optimal mobile network based on information collected from a system. CONSTITUTION: A previous register(110) compares a SNR(Signal to Noise Ratio) of a first network with a first threshold value. If a first relational condition is satisfied, the previous register performs a previous registration procedure to a target network. A handover performer(120) compares the signal-noise ratio with a second critical value. If the second relational condition is satisfied, the handover performer performs a handover procedure to the target network.

Description

Handover apparatus and method for preventing time delay in the heterogeneous networks

The present invention relates to a handover technology in a multi-air interface environment in which a plurality of radio access networks are overlapped, and more particularly, to an apparatus and a method for inter-heterogeneous handover that prevent time delay.

The present invention is derived from a study conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunications Research and Development. .

The next generation mobile communication network is evolving into a form in which various mobile networks such as cellular network, WiBro network, and WLAN network are harmonically connected and converged through an IP-based core network. Access) supports various data rates.

In the next generation mobile communication network, the user may want to receive seamless services while moving between access networks to the same network and heterogeneous network regardless of the wireless access technologies of various mobile networks.

To this end, next-generation mobile communication networks consider the service features of each wireless access system such as user's cost, data rate, and coverage to provide seamless services to users. Network level support is needed to access and provide the best mobile network.

Accordingly, the present inventors have studied a technology capable of supporting a seamless service to a user by reducing handover delay time and data loss in a handover between heterogeneous networks in a multi-air interface environment.

The present invention has been invented under the above-mentioned object, and it is a heterogeneous inter-network handover device that prevents time lag that can support seamless service to users by reducing handover delay time and data loss during heterogeneous network handover in a multi-air interface environment. And to provide a method.

According to an aspect of the present invention for achieving the above object, the present invention is characterized in that the pre-registration procedure and the handover procedure is performed separately when performing handover between heterogeneous networks in a multi-air interface environment.

According to an additional aspect of the present invention, the present invention is characterized in that the optimal mobile network is selected based on the resource information collected from the user terminal and the system at the time of performing the pre-registration procedure and at the time of performing the handover.

Therefore, the present invention separates the pre-registration procedure and the handover procedure when performing handover between heterogeneous networks in a multi-air interface environment, and collects them from the user terminal and the system at the time of performing the pre-registration procedure and the time of handover. By selecting the optimal mobile network based on the information, it has a useful effect of supporting the seamless service to users by reducing handover delay time and data loss.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand and reproduce the present invention.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the embodiments of the present invention may unnecessarily obscure the gist of the present invention.

Prior to describing the present invention, terms used throughout the specification are defined. These terms are terms defined in consideration of functions in the embodiments of the present invention, and are terms that can be sufficiently modified according to the intention, convention, etc. of the user or operator, and the definitions of these terms are based on the contents throughout the specification of the present invention. Will have to be lowered.

The multi-air interface environment refers to an environment in which a plurality of radio access networks are overlapped, and the plurality of radio access networks are fused with an IP core (backbone) network.

Pre-registration refers to a state in which the user terminal performs initial access and authentication on the target network to be handed over without completely handing over from the currently connected mobile network to the target network.

1 is a schematic diagram of the present invention. Referring to FIG. 1, a WLAN (WLAN) network is connected to an IP backbone (core) network as a first network, and an LTE-Evolution-advanced network is connected to a second network to form a multi-air interface environment. It can be seen that. In the figure, a WLAN network is implemented to exist as a hot spot of an LTE-evolution network.

The user equipment (UE) 200 supports a dual mode that can accommodate both a wireless LAN network and an LTE-evolution network, and provides various packet services through handover between these two heterogeneous networks. .

In the figure, an evolved NodeB (eNodeB) manages a Radio Resource and sets up a Radio Bearer. It collects the information of the radio link.

A mobility management entity (MME) controls and manages handovers between base stations (inter-network handovers) and performs session management.

Serving Gateway (S-GW) serves to control the creation and release of radio bearers and performs a mobility access gateway (Mobility Access Gateway) function to support IP mobility.

A packet data network gateway (P-GW) performs a local mobility anchor function to control radio bearer creation and release and to support IP mobility.

A multi-radio resource management function (MRRMF) collects and manages radio resources, and implements handover by implementing a heterogeneous inter-network handover device 100 to prevent time delay, for example, according to the present invention. Pre-registration and handover execution can be controlled to determine the optimal access network.

The access network discovery and selection function (ANDSF: access network discovery and selection function) performs a function of providing the neighboring network information to the user terminal (200).

Authentication server (AAA: Authentication, Authorization, Account) performs authentication and authorization.

The Policy and Charging Rule Function (PCRF) performs quality of service (QoS) policy setting and charge management.

An access point (AP) performs a wireless access function between the user terminal 200 and a WLAN network, and collects and reports radio resource information of the WLAN to a higher level.

A WLAN gateway (WGW) reports radio resource information received from an access point (AP) to a multiple radio resource management function (MRRMF) and performs a mobility access gateway function to support IP mobility. do.

2 is a block diagram according to an embodiment of a heterogeneous inter-network handover apparatus for preventing time delay according to the present invention. As shown in the figure, the heterogeneous inter-network handover apparatus 100 for preventing time delay according to this embodiment includes a pre-registration unit 110 and a handover execution unit 120.

The pre-registration unit 110 compares the signal-to-noise ratio (SNR) of the first network and the first threshold value measured by the user terminal 200 to the target network to be handed over if the first comparison condition is satisfied. To perform the pre-registration procedure.

The handover performing unit 120 compares the signal-to-noise ratio (SNR) of the first network measured by the user terminal 200 with the second threshold after the pre-registration process is performed by the pre-registration unit 110. If the second comparison condition is satisfied, the handover procedure to the target network is performed.

In this case, when the access network currently connected to the user terminal 200 is the first network and the target network is the second network, the first threshold is the maximum threshold Th _MAX , and the first comparison condition is the first network. Determine whether the signal-to-noise ratio (SNR) is less than the maximum threshold (Th _MAX ), the second threshold is the minimum threshold (Th _MIN ), the second comparison condition is that the signal-to-noise ratio (SNR) of the first network is the minimum threshold ( Th _MIN ) may be determined.

Meanwhile, when the access network is the second network and the target network is the first network, the first threshold is the minimum threshold Th _MIN , and the first comparison condition is that the signal-to-noise ratio SNR of the first network is the minimum threshold Th. _MIN ), the second threshold is the maximum threshold (Th _MAX ), the second comparison condition is a determination day whether the signal-to-noise ratio (SNR) of the first network is greater than the maximum threshold (Th _MAX ) Can be.

For example, as shown in FIG. 1, it is assumed that a WLAN network is adopted as a first network and an LTE-evolution network is used as a second network.

The LTE-evolution network does not have a large change in signal strength of the base station (eNodeB) because of its wide coverage, but the WLAN (WLAN) network has a large change in signal strength of an access point (AP) because of its small coverage.

Accordingly, the heterogeneous network handover apparatus 100 for measuring the signal-to-noise ratio (SNR) value by receiving the signal strength of the access point (AP) and preventing time delay according to the present invention is the heterogeneous network handover. It is assumed that the signal to noise ratio (SNR) value of the access point (AP) measured by the user terminal 200 is used to perform the procedure.

The heterogeneous inter-network handover apparatus 100 for preventing time delay according to the present invention includes a first threshold value and a second threshold value, which are two threshold values which previously set a signal-to-noise ratio (SNR) of an access point (AP) received from the user terminal 200. In comparison with the threshold, if the comparison condition is satisfied, the pre-registration procedure and the handover procedure are performed.

The reason for having two thresholds is that if a handover procedure is performed when one threshold is satisfied and a comparison condition is satisfied, a delay may occur in the handover due to a time-consuming authentication process.

In addition, after completing the handover procedure and connecting from the access network (source network) to the target network, if the signal state of the source network suddenly improves or the signal state of the target network worsens, the handover procedure is performed again to the source network. Because things can happen.

Therefore, in the present invention, the first threshold value and the second threshold value are set to more dynamically respond to changes in the signal states of the source network and the target network during handover, and when a comparison condition with respect to the first threshold value is satisfied. Perform pre-registration procedure to perform basic connection and authentication to the target network.

After the pre-registration procedure is performed, if the comparison condition for the second threshold is satisfied, the handover procedure may be performed immediately to prevent time delay due to authentication during handover through the pre-registration procedure.

In addition, it is possible to perform a more flexible handover processing procedure than the existing handover method by preventing a handover repetition that can frequently occur due to a change in the signal state of the source network and the target network through a pre-registration procedure.

3 and 4 are exemplary diagrams illustrating a signal-to-noise ratio (SNR) of a WLAN network measured by a user terminal over time.

3 illustrates a signal-to-noise ratio (SNR) of a WLAN network measured by a user terminal when the UE performs heterogeneous network handover from the LTE-evolution network to the WLAN network.

In the figure, it can be seen that the signal-to-noise ratio (SNR) increases over time. Therefore, when the signal-to-noise ratio (SNR) increases over time, the first threshold, which is a pre-registration point for processing to perform the pre-registration procedure, must be the minimum threshold Th _MIN , and the first threshold and the signal-to-noise ratio ( The first comparison condition comparing the SNR should be a determination as to whether the signal-to-noise ratio SNR is greater than the minimum threshold Th _MIN .

On the other hand, the second threshold which is a handover time processing to perform the handover procedure should be the maximum threshold (Th _MAX ), the second comparison condition for comparing the second threshold with the signal-to-noise ratio (SNR) is the signal band of the first network It should be determined whether the noise ratio (SNR) is greater than the maximum threshold (Th _MAX ).

4 illustrates a signal-to-noise ratio (SNR) of a WLAN network measured by a user terminal when the UE performs heterogeneous network handover from a WLAN network to an LTE-evolution network.

In the figure, it can be seen that the signal-to-noise ratio (SNR) decreases over time. Therefore, if the signal-to-noise ratio (SNR) decreases over time, the first threshold, which is a pre-registration point for processing to perform the pre-registration procedure, should be the maximum threshold value (Th _MAX ), and the first threshold and the signal-to-noise ratio ( The first comparison condition comparing SNR should be a determination as to whether the signal-to-noise ratio (SNR) is less than the maximum threshold Th _MAX .

On the other hand, the second threshold value that is the handover time to process the handover procedure should be the minimum threshold (Th _MIN ), the second comparison condition for comparing the second threshold value and the signal-to-noise ratio (SNR) is the signal band of the first network It should be determined whether the noise ratio SNR is less than the minimum threshold Th _MIN .

Meanwhile, according to an additional aspect of the present invention, the pre-registration unit 100 performs a pre-registration procedure to the target network to be handed over by further reflecting preference information collected from the user terminal and resource information collected from the system. It can also be processed.

For example, the preference information may be a network preference of the user considering service characteristics of each wireless access network such as cost, data transmission rate, coverage, and the like. In this case, the target network may be selected by reflecting the user's network preference priority.

For example, when reflecting the resource information, it is determined whether the amount of resources requested by the user terminal is smaller than the amount of available resources and the number of user terminals being serviced is smaller than the maximum number of terminals that can be connected. It can be implemented to perform the registration process.

Therefore, by doing so, the present invention separates and performs the pre-registration procedure and the handover procedure when performing handover between heterogeneous networks in a multi-air interface environment, but at the time of performing the pre-registration procedure and the time of handover. By selecting the optimal mobile network based on the information collected from the system, handover latency and data loss can be reduced to provide seamless service to users.

A handover operation between heterogeneous networks for preventing time delay according to the present invention will be described with reference to FIGS. 5 and 6. 5 is a flowchart according to an embodiment of a pre-registration performing procedure, and FIG. 6 is a flowchart according to an embodiment of a handover performing procedure.

Referring to FIG. 5, the pre-registration step S100 is performed. First, the heterogeneous inter-network handover device 100 that prevents time delay according to the present invention measures the signal network of the first network measured from the user terminal 200 in step S110. Receives a Signal to Noise Ratio (SNR).

In this case, the user terminal 200 may periodically report the signal-to-noise ratio (SNR) of the first network and report it to the handover device 100 at a request from the handover device 100. have.

When the signal-to-noise ratio (SNR) of the first network is received by the step S110, the handover device 100 compares the signal-to-noise ratio (SNR) of the first network and the first threshold value received in step S120.

When the first comparison condition is satisfied as a result of the comparison in step S120, the handover apparatus 100 processes to perform a pre-registration procedure for the target network to be handed over in step S130.

At this time, according to an additional aspect of the present invention, the pre-registration step (S100) may be implemented to reflect the preference information collected from the user terminal in step S122, and to reflect the resource information collected from the system in step S124.

For example, the preference information may be a network preference of the user considering service characteristics of each wireless access network such as cost, data transmission rate, coverage, and the like. In this case, the target network may be selected by reflecting the user's network preference priority.

For example, when reflecting the resource information, the target network to be handed over may be selected by determining whether the amount of resources requested by the user terminal is smaller than the amount of available resources and the number of user terminals being serviced is smaller than the maximum number of terminals that can be connected.

Referring to Figure 6, the handover step (S200), after the pre-registration process is performed by the pre-registration step (S100), heterogeneous network handover device 100 to prevent time delay according to the present invention is In operation S210, a signal to noise ratio (SNR) of the first network measured from the user terminal 200 is received.

When the signal-to-noise ratio (SNR) of the first network is received in step S210, the handover device 100 compares the signal-to-noise ratio (SNR) of the first network received in step S220 with the second threshold.

When the second comparison condition is satisfied as a result of the comparison in step S220, the handover apparatus 100 processes to perform a handover procedure to the target network in step S230. At this time, the handover apparatus 100 transmits a request message for handover processing to the source network, the target network and the user terminal 200 so that the user terminal releases the connection with the source network and accesses the target network.

In the above, when the access network currently connected to the user terminal 200 is the first network and the target network is the second network, the first threshold is the maximum threshold Th _MAX , and the first comparison condition is the first network. Determine whether the signal-to-noise ratio (SNR) is less than the maximum threshold (Th _MAX ), the second threshold is the minimum threshold (Th _MIN ), the second comparison condition is that the signal-to-noise ratio (SNR) of the first network is the minimum threshold ( Th _MIN ) may be determined.

Meanwhile, when the access network is the second network and the target network is the first network, the first threshold is the minimum threshold Th _MIN , and the first comparison condition is that the signal-to-noise ratio SNR of the first network is the minimum threshold Th. _MIN ), the second threshold is the maximum threshold (Th _MAX ), and the second comparison condition is a determination of whether the signal-to-noise ratio (SNR) of the first network is greater than the maximum threshold (Th _MAX ). Can be.

By doing so, the present invention separates and performs the pre-registration procedure and the handover procedure when performing handover between heterogeneous networks in a multi-air interface environment, but at the time of performing the pre-registration procedure and the handover time. By selecting the optimal mobile network based on the information collected from it, it is possible to support the seamless service to the user by reducing the handover delay time and data loss, it is possible to achieve the above object of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. .

The present invention can be industrially used in the field of handover technology and its application technology in a multi-radio interface environment in which a plurality of radio access networks are overlapped.

1 is a schematic diagram of the present invention

2 is a block diagram according to an embodiment of an inter-network handover apparatus for preventing time delay according to the present invention.

3 and 4 are exemplary views showing signal-to-noise ratio (SNR) of a WLAN network measured by a user terminal over time.

5 is a flowchart according to an embodiment of a pre-registration performing procedure.

6 is a flowchart according to an embodiment of a handover performing procedure.

<Explanation of symbols for the main parts of the drawings>

100: handover device 110: pre-register

120: handover performing unit 200: user terminal

Claims (10)

Pre-processing to compare the signal-to-noise ratio (SNR) of the first network measured by the user terminal and the first threshold value, and to perform a pre-registration procedure to the target network to be handed over if the first comparison condition is satisfied. A register; After the pre-registration process is performed by the pre-registration unit, the signal-to-noise ratio (SNR) of the first network measured by the user terminal is compared with the second threshold, and when the second comparison condition is satisfied, a handover procedure to the target network is performed. A handover performer which processes to perform; Heterogeneous inter-manganese handover device, characterized in that comprising a time delay. The method of claim 1, The pre-registration unit: A device for heterogeneous inter-network handover prevention, comprising: processing to perform a pre-registration procedure to a target network to be handed over by further reflecting preference information collected from a user terminal and resource information collected from a system. The method according to claim 1 or 2, If the access network is the first network and the target network is the second network, The first threshold is the maximum threshold Th _MAX ; The first comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is smaller than the maximum threshold Th _MAX ; The second threshold is the minimum threshold Th _MIN ; And the second comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is smaller than the minimum threshold Th _MIN . The method according to claim 1 or 2, If the access network is the second network and the target network is the first network, The first threshold is the minimum threshold Th _MIN ; The first comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is greater than the minimum threshold Th _MIN ; The second threshold is the maximum threshold Th _MAX ; And the second comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is greater than the maximum threshold (Th _MAX ). The method of claim 2, The pre-registration unit: It is determined that the amount of resources requested by the user terminal is smaller than the amount of available resources, and the number of user terminals being serviced is smaller than the maximum number of terminals that can be connected. Heterogeneous handover device for preventing time delay. Receiving a signal to noise ratio (SNR) of the first network measured from the user terminal; Comparing the signal-to-noise ratio (SNR) of the first network and the first threshold received by the step; Processing to perform a pre-registration procedure for a target network to be handed over when the first comparison condition is satisfied as a result of the comparison by the above step; Heterogeneous handover method for preventing time delay, characterized in that comprising a pre-registration step comprising. The method of claim 6, The heterogeneous handover method for preventing the time delay is: Receiving a signal-to-noise ratio (SNR) of the first network measured from the user terminal after the pre-registration procedure is performed by the pre-registration step; Comparing the signal-to-noise ratio (SNR) of the first network and the second threshold received by the step; Processing to perform a handover procedure to a target network when the second comparison condition is satisfied as a result of the comparison by the above step; A handover method between heterogeneous networks for preventing time delay, characterized by further comprising a handover step. 8. The method according to claim 6 or 7, The pre-registration step is: Reflecting preference information collected from the user terminal; Reflecting the resource information collected from the system; The heterogeneous handover method for preventing time delay, characterized in that it further comprises. The method of claim 7, wherein If the access network is the first network and the target network is the second network, The first threshold is the maximum threshold Th _MAX ; The first comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is smaller than the maximum threshold Th _MAX ; The second threshold is the minimum threshold Th _MIN ; And wherein the second comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is smaller than the minimum threshold Th _MIN . The method of claim 7, wherein If the access network is the second network and the target network is the first network, The first threshold is the minimum threshold Th _MIN ; The first comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is greater than the minimum threshold Th _MIN ; The second threshold is the maximum threshold Th _MAX ; And the second comparison condition is a determination as to whether the signal-to-noise ratio (SNR) of the first network is greater than the maximum threshold (Th _MAX ).

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